Pressure reducing valve



April 16, 1935.

P. c. TEMPLE I v PRESSURE REDUCING VALVE Original Filed Sept. 2, 1931Reiaued Apr. 16, 1935 rams soar: acnocmo'vuvr: Paul 0. Temple, Decatur,111., assignor to A. w.

Cash Company, Delaware Decatur, Ill., a corporation of Y Original No.1,934,832, dated November 14, 1933,

Serial No. 560,704, September 2, 1931. Application for reissue August15, 1934, Serial No.

8 Claims.

My invention relates to pressure-reducing valves and the like.

tical'difliculty, particularly when the pressure is reduced from a veryhigh pressure to a quite low pressure as in ammonia expansion valves,for example. The cutting of the valve seat through wiredrawing is causedby the passage of the high pressure fluid at high velocity through" thenarrowly opened or cracked valve from the high pressure side to the lowpressure side of thevalve, resulting in impaired efficiency and reducedserviceable life of the valve. In an ordinary ammonia expansion valve,say where the pressure is reduced from 1'70 pounds to 20 pounds, merelyby way of example, the drop in pressure across the seat is veryconsiderable, i. e., pounds in the example assumed. With such differencein pressure the valve is only cracked of! its seat to produce normalflow. The cracked valve and the high differential pressure withattendant 'highvelocities cause excessive wire-- drawing and wear of theseat.

A principal object of my invention is to overcome wiredrawing and at thesame time increase the efliciency of the device by eliminating the abovementioned causes of wiredrawing. To this end I provide means whichpermits the valve to open wide and causes but a relatively small drop inpressure across the valve seat with attendant minimum velocity. Moreparticularly, I provide in the structure a passage for the fluid afterit has passed the valve seat such that the drop in pressure and velocityare greatly reduced so as to avoid wire cutting, without, however,danger of the passage being plugged up due to any foreign matter. In mypreferred form of embodiment, I provide a long tortuous groove be- .weenthe body of the valve and its housing to materially resist the flow andthus attain the above mentioned advantages. Another object of theinvention is to provide a self-creeping valve (i. e., one that turns onits seat) to obtain a grinding action, which tends to prevent wear inone place, maintains the valve in tight closure condition, and enhancesthe elliciency and lengthens the life of the device.

Another object of my invention is to prevent liquefaction orsolidification ofthe refrigerating gas within the low pressure side ofthe casing. To this end, I provide a packless valve device including ahousing for the plunger valve with the housing extending from the highpressure side to the delivery opening, the operating connections for theplunger valve being outside of, the housing so that no packing isnecessary or leak is possible.

Still another object of my invention is to provide a novel arrangementwhereby the valve may be easily and quickly removed from the line forthe purpose of inspection, repair or cleansing.

Numerous other objects and advantages will be apparent as the inventionis better understood from the following description, which, taken inconnection with the drawing, discloses a preferred embodiment thereof.

On the drawing: a

Figure 1 is a vertical longitudinal section through the valve; and

Fig. 2 is an end view with part of the casing broken away.

The valve shell or body comprises two parts or castings 3 and 4 havingmeeting flanges held together by bolts in the usual way. A diaphragm 5,having its edges clamped between the two castings, divides the valvebody into a control pressure chamber 6 and a spring chamber 1, thelatter housing the usual loading spring 8. The body part 3 has integraltherewith a downward extension 8 in which is mounted the usual strainerunit l0. Within the body part 3 is a partition I l separating thepressure control chamber 6 from a small chamber l 2 above the strainer.The high pressure side of the valve includes an inlet opening I30. in acoupling l3 into which the end I of the inlet pipe isscrewed, thepassage It in which the strainer is positioned and the chamber i2.Screwed into a threaded opening it in the partition II is the reducedend of a tubular valve housing l1, having a small inlet passage and anenlarged bore l8 in which slides a plunger valve IS. The end of thevalve which is preferably, though not necessarily, rounded, normallyengages a valve seat 20 in the housing I1. The body of the valve I9 isprovided with a tortuous groove I9a which together with the housing I!forms a closed channel or path from one end to the other. Preferably,the groove runs spirally around the plunger valve and the groove is ofsuch width as to assist in-resisting flow without danger of becomingplugged up. Slidably mounted on the valve housing I! is a sleeve 22carrying a pin 23 in one end and engaging the flat end of the valve IS.The sleeve 22 projects through a collar 21 mounted in an opening in thecasting 3 and also projects into an opening into a coupling member 28into which the end of the delivery pipe is screwed. A circular rib 24 onthe forward end of the sleeve 22 has an inclined arcuate face whichcoacts with a beveled face of a ring 25. .A passage I90, the plungervalve "creeps" or turns bell crank lever 28, mounted on a stud 21, has

the forks of its arm 29 straddling the sleeve 22 and pressing againstthe ring 25 at points on the opposite sides of the axis of the ring.

The other forked armiil of the lever 26 straddles a stud 3| whichdepends from the diaphragm 5 and carries a ring 32 coacting with a nut33. The customary bearing plate 3| and the diaphragm 5 are clampedtogether between a flange 35 onthe stud 3| and a nut 36 screwed on theupper reduced end of this stud.

The normal reduced pressure, that is, the pressure in the delivery lineduring zero demand, is such as to exert such force on the underside ofthe diaphragm as to keep the valve closed against the pressure exertedon the upper side of the diaphragm by the atmosphere and the spring 8and against the pressure exerted by the high pressure fluid on the endof the valve l9 exposed to theopening Ii. When the pressure in thedelivery line is reduced by demand of the refrigerating or otherapparatus, the pressure in the delivery line drops slightly and as thecontrol pressure-space B is in communication with the delivery openingthrough a narrow annular space 31 between the sleeve 22 and the collar2|, the pressure in the control chamber drops correspondingly. Thus thepressure load on the underside of the diaphragm is decreased and thediaphragm moves downwardly and as movement of the lever 26 is permittedthe initial high pressure of fluid in the opening I 6 moves the valvepermitting the fluid to pass the valve seat 20, through the spiralgroove Ho and out into the delivery line. As the fluid passes into thedelivery line it creates a suction or aspirating effect delivery pipebuilds up to normal reduced pressure and then the valve seeks andmaintains a definite position so long as the demand remains normal.Should the demand continue to increase, the velocity of the fluidpassing the aspirating opening will further weaken the pressure in thecontrol pressure space and the valve would open further to acorresponding extent. As the demand falls off the pressure in thedelivery pipe in the control pressure space builds up and the valvefinally closes when the pressure becomes normal.

If the pressure of the fluid were greatly reduced as it passed the valveseat when thevalve is cracked, its velocity at that point would be con-,siderable with the result that the seat would be out due tothe"wiredrawing" as explained above. To prevent such reduction andvelocity at that point and thus eliminate cutting of the seat, 1 causethe fluid, after it has passed the seat, to travel through the tortuousgroove "a, which is preferably narrow and spiral in form, and thus delayany considerable reduction in pressure until the fluid passes out of thespiral groove. Due to the friction of the fluid with the walls of thegroove, the narrownes of the groove and the tortuous path which itprescribes, the groove offers great resistance against the fluid flowand thus the reduction of pressure and velocity of the fluid as it thevalve seat is minimized so that there is no deterioration of the seat.It will be that, due to the reaction of the spiral course of the fluidthrough thetm'tuoiis without departing from the and scope of 75-slightly on its seat each time it opens and closes. Thisself-grindingaction prevents localized wear, keeps the seats in primecondition, and makes fortight closure over a longer period of time thanotherwise would be true.

It will also be observed that the refrigerating gas does not expanduntil-it reaches the delivery opening and that there is no materialexpansion of the gas in the pressure control chamber 6 or in the valvehousing. I"! so that the gas does not liquefy or solidify either in thatchamber or the valve housing. Liquefaction or freezing causes thelubricant to congeal with consequent interference with the normaloperation of the valve and the exterior becomes frosted, which likewiseimpairs the eflicien'cy. It will be particularly observed that I obtainthis desirable result without the use of any packing or stufling boxeswhich are troublesome, leaky and otherwise obiectionable. complished byhaving the sleeve 22 extend into the delivery opening, and providingvalve operating connections which operate the plunger valve withoutextending into the housing. I

Each of the coupling members I3 and 28 has an annular groove 40 intowhich is fitted a flange .ll on the corresponding end of the body member1 to center properly the valve in the line. Bolts I} on either side ofthe valve project through openings in the coupling'members in order tosecurethe coupling members and valve in assembled relation. It will beevident that when the valve is to be removed for the purposes ofinspection, cleaning or repair, it is only necessary to loosen thenutson the bolts 43, move the coupling members l3 and 28 apart to carrytheir grooves 40 away from the flanges ti, and then lift out the valve.

' It has been found that wiredrawing occurs most when a valve isslightly cracked ofl' its seat, because seat velocity is highes't 'undersuch a condition. The valve of the instant invention is so constructedthat it cannot assume a slightly cracked position. It will be apparentthat this is due to the difference between the seating area .of theplunger valve l9, and-the area of the plunger, itself, where the plungerfits into enlarged bore ll of valve housing H.

In operation, the valve definitely snaps open and shut. For example,when the valve isin closed position, and there is 170 lbs. pressureeffective over the seating area, a slight drop in pressure in thecontrol pressure chamber permits the valve to start opening, andinstantaneously 170 lbs. pressin'e becomes effective over the full areaof plunger I 9 which causes a greater unbalanced relation between it andthe diaphragm load, and because of this the valve snaps open,

compelling spiral channel ISa to do all the work of pressure reduction.When the pressure desired in the control chamber is approached and thevalve starts toclose, as soon as it starts to throttle flow it snapsshut instantaneously, be-

cause the full inlet pressure of 170 lbs. is no longer effective overthe entire area of plunger I! and is only reflective over the seatingarea. There is therefore, no period of cracked valve po-f sitiontoproduce wiredrawing.

It is thought that the invention and many of its attendant advantageswill be understood from the foregoing description, and it will be.apparform, construction and arrangement of the parts v 7 19,540 theinvention or sacrificing all of its material adfluid from the highpressure side to the'reduced pressure side and including a valve seatand avalve member co-operating therewith, and means providing a spiralflow-resisting path for the fluid after it has .passed said seat toprevent wiredrawing.

r 2. In a device of the class described, a casing having a partitiondividing the casing into a high pressure 'chamber and a pressure controlchamber and said casing also having .a delivery opening, a tubular valvehousing unbroken from end to end, mounted in said partition and having avalve seat; a valve member mounted in said housing, a sleeve slidable onsaid housing and cooperating with said valve member, with one end ofsaid sleeve projecting into said delivery opening and providing anaspirating passagebetween said delivery opening andv said pressurecontrol chamber, a pressure responsive member, and connections betweensaid last mentioned member and said sleeve.

3. In a device of the class described, a casing having a partitiondividing the easing into a high pressure side and a low pressure side, atubular valve housing mounted in said partition and having a valve seat,a plunger valve mounted in said housing and having one end cooperatingwith said seat, the plunger valve having a tortuous groove forming anarrow path for the fluid after it has passed the valve seat, a sleeveslidable on said housing. means, carried by the sleeve and engaging theother end of said plunger valve, a pressure responsive member andconnections between said pressure responsive member and said sleeve.

4. In a device for reducing the pressure of a ually reduced and materialexpansion of the 'fluid is prevented.

5. In a device for reducing the pressure of a refrigerant fluid having ahigh pressure chamber and a delivery'opening, a valve device including avalve, a valve seat, and means comprising 'a'spiral' channel extendingfrom said valve to said delivery opening for allowing but a relativelysmall drop in pressure across said valve seat to prevent excess wear ofsaid seat when the valve is opened wide.

6. In a device for reducing the pressure of a Q passage extending fromsaid valve to said re-' duced pressure chamber, whereby the pressure ofthe fluid on one side of said valve seat is maintained substantiallyequal to the pressure on the V other side to prevent wiredrawing whensaid valve is opened.

7. In a device for reducing the pressure of a refrigerant fluid having ahigh pressure space and a delivery opening, a valve member therebetweencomprising avalve at the high pressure end and a spiral groove extendingfrom said valve to saiddelivery opening, whereby the pressure of thefluid flowing therethrough is gradually reduced and said valve member isrotated slightly by the, fluid.

8. In a device for reducing the pressure of a refrigerant fluid having ahigh pressure chamher. and a reduced pressure chamber, a tubular housingbetween said chamber and having a. valve seat therein, and a valvemember in said housing comprising a valve at one end adapted toco-operate with said valve seat and a spiral passage extending from saidvalve to said reduced pressure chamber, whereby the pressure on one sideof said valve seat is maintained substantially equal to the pressure onthe other side to preventwiredrawing when said valve is opened, and thefluid passing therethrough causes a relative rotational movement betweensaid seat and said valve member.

PAUL c. TEMPLE.

